content: /*
   * The MIT License
   * Copyright (c) 2012 Microsoft Corporation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  package microsoft.exchange.webservices.data.dns;
  
  import org.xbill.DNS.Lookup;
  import org.xbill.DNS.Record;
  import org.xbill.DNS.SRVRecord;
  import org.xbill.DNS.Type;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import microsoft.exchange.webservices.data.core.exception.dns.DnsException;
  
  /**
   * Class that represents DNS Query client.
   */
  public class DnsClient {
      /**
       * Performs Dns query.
       *
       * @param <T>              the generic type
       * @param cls              DnsRecord Type
       * @param domain           the domain
       * @param dnsServerAddress IPAddress of DNS server to use (may be null)
       * @return DnsRecord The DNS record list (never null but may be empty)
       * @throws DnsException the dns exception
       */
      public static <T extends DnsRecord> List<T> dnsQuery(Class<T> cls, String domain, String dnsServerAddress) throws
              DnsException {
          System.out.println("dnsQuery(" + domain + ", " + dnsServerAddress + ")");
          List<T> dnsRecordList = new ArrayList<T>();
  
          try {
              Record[] records = new Lookup(domain, Type.SRV).run();
              if (records != null) {
                  for (Record record : records) {
                      SRVRecord srvRecord = (SRVRecord) record;
                      System.err.println("dnsQuery() found: " + srvRecord.rdataToString());
  
                      T dnsRecord = cls.newInstance();
  
                      // Loads the DNS SRV record
                      dnsRecord.load(srvRecord.rdataToString());
                      dnsRecordList.add(dnsRecord);
                  }
              } else {
                  System.err.println("No results");
              }
          } catch (Exception e) {
              throw new DnsException(e.getMessage());
          }
  
          return dnsRecordList;
      }
  }
  